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Croton Tiglium

Bitki adı: Croton Tiglium

Bilimsel adı: Croton tiglium

Cins: Croton

Familya: Euphorbiaceae

Genel Bilgiler

Bilimsel Araştırmalar

Essential Oils: Chemistry and Pharmacological Activities.

In this review, we provide an overview of the current understanding of the main mechanisms of pharmacological action of essential oils and their components in various biological systems. A brief introduction on essential oil chemistry is presented to better understand the relationship of chemical aspects with the bioactivity of these products. Next, the antioxidant, anti-inflammatory, antitumor, and antimicrobial activities are discussed. The mechanisms of action against various types of viruses are also addressed. The data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Therefore, these natural products can be a promising source for the development of new drugs.

Makaleyi görüntüle

Protein kinase C: perfectly balanced.

Protein kinase C (PKC) isozymes belong to a family of Ser/Thr kinases whose activity is governed by reversible release of an autoinhibitory pseudosubstrate. For conventional and novel isozymes, this is effected by binding the lipid second messenger, diacylglycerol, but for atypical PKC isozymes, this is effected by binding protein scaffolds. PKC shot into the limelight following the discovery in the 1980s that the diacylglycerol-sensitive isozymes are "receptors" for the potent tumor-promoting phorbol esters. This set in place a concept that PKC isozymes are oncoproteins. Yet three decades of cancer clinical trials targeting PKC with inhibitors failed and, in some cases, worsened patient outcome. Emerging evidence from cancer-associated mutations and protein expression levels provide a reason: PKC isozymes generally function as tumor suppressors and their activity should be restored, not inhibited, in cancer therapies. And whereas not enough activity is associated with cancer, variants with enhanced activity are associated with degenerative diseases such as Alzheimer's disease. This review describes the tightly controlled mechanisms that ensure PKC activity is perfectly balanced and what happens when these controls are deregulated. PKC isozymes serve as a paradigm for the wisdom of Confucius: "to go beyond is as wrong as to fall short."

Makaleyi görüntüle

A tumor promoter induces rapid and coordinated reorganization of actin and vinculin in cultured cells.

Treatment of epithelial African green monkey kidney (BSC-1) cells with the potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) induces a rapid and reversible redistribution of actin and vinculin that is detectable after only 2 min of treatment. Within 20-40 min, stress fibers disappear, while at the same time large actin-containing ribbons resembling ruffles develop both at the cell periphery and in more central regions. Vinculin is associated with these actin ribbons or bands in a punctate or patchy staining pattern. Adhesion to the substratum is changed from predominantly focal contacts associated with stress fiber ends in untreated cells to broad zones of close contact after TPA treatment. High voltage electron microscopic observations disclose the ribbons to consist of highly cross-linked actin filament networks. Thus, association of vinculin with filament networks, rather than (the ends of) filament bundles, is demonstrated. The integrity of microtubules and vimentin filaments is not affected by TPA treatment, but their distribution is altered to conform with the highly distorted cell shape. The response to TPA is neither prevented nor modified by nocodazole-induced depolymerization or taxol-induced stabilization of microtubules. An intact intermediate filament network seems not required either since colcemid-induced collapse of vimentin filaments towards the nucleus does not affect the cell's response to TPA. Rapid redistribution of actin and vinculin also takes place in enucleated cells and in the presence of cycloheximide, but is prevented by dinitrophenol or oligomycin. TPA-induced cytoskeletal alterations are independent of fibronectin expression and not mimicked, modified, or prevented by calmodulin inhibitors or experimentally elevated levels of calcium and cyclic AMP. Thus the morphological response to TPA involves rapid redistribution of actin and vinculin independent of transcription and translation, fluctuations in the levels of calcium or cyclic AMP, or changes in the organization of microtubules, intermediate filaments, and fibronectin.

Makaleyi görüntüle

Synthesis of a fibrinolytic activator and inhibitor by endothelial cells.

Vascular endothelial cells derived from rabbit vena cava and maintained in continuous culture exhibited properties characteristic of the intact endothelium. These cells were used as a model for characterizing the fibrinolytic components specified by the endothelium. Endothelial cells in culture digested radiolabeled fibrinogen. Digestion resulted from the synthesis and secretion of a plasminogen activator. Fibrinolysis was not detected when cells were grown in medium lacking plasminogen, indicating the absence of plasminogen-independent fibrinolytic enzymes. Phorbol-myristate-acetate increased extracellular plasminogen activator activity dramatically. This increase was prevented when actinomycin D or cycloheximide was included in the growth medium, indicating that new gene expression was required for it. Intracellular plasminogen activator could not be detected unless the cell extracts were exposed briefly to mildly acidic conditions. Mixing experiments between acid-treated and untreated extracts suggested that the cells contained a potent, acid-labile inhibitor of fibrinolysis. As little as 10 mug of protein from whole cell extracts inhibited both cell and urokinase-mediated fibrinolysis by more than 70%. Cell fractionation studies localized the inhibitor to the cytosol whereas plasminogen activator activity was restricted to the membrane-rich fraction. This membrane fraction did not require acidification for activity, suggesting that the inhibitor had been removed and that acidification did not activate a plasminogen proactivator. These observations demonstrate that regulation of endothelial fibrinolytic activity is far more complex than had been anticipated and raise several uncertainties in regard to detecting the presence of plasminogen activators in cells and tissues.

Makaleyi görüntüle

Cocarcinogenic principles from the seed oil of Croton tiglium and from other Euphorbiaceae.

Kaynak: James A. Duke

Kaynaklar ve Görseller

File:The American Flora. Vol. 1, 1855 - pl. 28 Croton tiglium (6022334832).jpg

File:Jamalgota-Croton-Tiglium-Fruits 03.jpg

File:Jamalgota-Croton-Tiglium-Fruits 02.jpg

File:Jamalgota-Croton-Tiglium-Fruits 01.jpg

File:Croton tiglium - Köhler–s Medizinal-Pflanzen-197.jpg

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